There are numerous medical conditions and procedures in which it is desirable or necessary to occlude hollow or tubular body organs such as, for example, blood vessels or to clamp together layers of tissue. One such example is in the treatment of venous complications, such as varicose veins, in which treatment involves selective occlusion of the veins. Other ducts, vessels or hollow body organs also may have to be obstructed or tissue layers clamped together for a variety of reasons. It would be desirable to provide devices and methods to effect occlusions of hollow body organs and to secure tissue layers to each other in a manner that that is easy and quick to apply.